1. Field of the Invention
The present invention relates to a network facsimile apparatus capable of conducting facsimile communication with a remote facsimile device via a PSTN (public switched telephone network) line and capable of connecting to a LAN (local area network) or similar network.
2. Description of the Related Art
Recently, network facsimile machines that are connected to PSTN telephone lines and to a LAN-type network have been developed. Using such a network facsimile machine allows picture data to be transmitted from network-connected computer devices to remote facsimile machines via the network facsimile machine. Alternatively, facsimile data received over the PSTN from remote facsimile machines can be delivered to the LAN-connected computer devices and their users (“clients”) via the network facsimile machine.
When facsimile data is sent from remote facsimile machines to a specified network-connected client, reception capabilities such as resolution and the like may differ from client to client. Just after communication is initiated between remote transmitter and network-connected receiver, normally the transmitter and receiver execute a pre-message procedure wherein the receiver declares its reception capabilities to the transmitter. When the fax transmission is to be delivered to a client device on the network, facsimile communication can be performed according to the reception capabilities of the recipient client to which delivery is to be made (“the delivery recipient”) by transmitting the reception capabilities of the delivery recipient to the remote facsimile machine.
Unfortunately, there are times when the client to whom final delivery is to be made cannot be specified when the receiver-side capabilities are declared. Consider a typical example of fax communication procedure as illustrated in FIG. 4 of the accompanying drawings, in which a network facsimile machine receives fax data from a remote facsimile machine. The transmitting machine is the remote facsimile machine, and the receiving side is the network facsimile. The network fax receives a CNG signal sent by the remote fax. After first transmitting a CED signal to the transmitting machine, the receiving machine transmits a DIS signal declaring its communication capabilities.
Next, a TSI signal indicating the Transmitter's Station Identification, and a SUB indicating a sub-address, for example, are transmitted by the transmitting machine to the receiving machine. When facsimile data is to be delivered to a specified client on the network, the SUB or TSI signal may be used to specify the client. The network facsimile, however, does not receive the SUB and TSI signals until after the receiving side sends its DIS signal indicating its capabilities, meaning that the identity of the final recipient is uncertain. In other words, the network facsimile doesn't know the reception capabilities of the machine that will take final delivery of the fax data when it transmits the DIS signal indicating the its reception capabilities.
Thus, the conventional network facsimile machine declares either its own communication capabilities, or the highest capabilities possessed by any of the client machines, and receives the fax data from the transmitting machine according to those capabilities. After reception, the network fax must then perform a conversion program to convert settings like resolution to suit the capabilities of the final recipient. If transmission to the network fax machine has been performed at the highest communication capabilities of any of the client machines and it turns out that those capabilities exceed the capabilities of the final recipient, it means that the time it takes to transmit the data is longer than it would have taken to transmit the data at the optimal settings.